import { readFileSync, readdirSync } from 'fs'

let idPerfix = ''
const svgTitle = /<svg([^>+].*?)>/
const clearHeightWidth = /(width|height)="([^>+].*?)"/g

const hasViewBox = /(viewBox="[^>+].*?")/g

const clearReturn = /(\r)|(\n)/g

function findSvgFile(dir) {
  const svgRes = []
  const dirents = readdirSync(dir, {
    withFileTypes: true
  })
  for (const dirent of dirents) {
    if (dirent.isDirectory()) {
      svgRes.push(...findSvgFile(dir + dirent.name + '/'))
    } else {
      const svg = readFileSync(dir + dirent.name)
          .toString()
          .replace(clearReturn, '')
          .replace(svgTitle, ($1, $2) => {
            let width = 0
            let height = 0
            let content = $2.replace(
                clearHeightWidth,
                (s1, s2, s3) => {
                  if (s2 === 'width') {
                    width = s3
                  } else if (s2 === 'height') {
                    height = s3
                  }
                  return ''
                }
            )
            if (!hasViewBox.test($2)) {
              content += `viewBox="0 0 ${width} ${height}"`
            }
            return `<symbol id="${idPerfix}-${dirent.name.replace(
                '.svg',
                ''
            )}" ${content}>`
          })
          .replace('</svg>', '</symbol>')
      svgRes.push(svg)
    }
  }
  return svgRes
}

export const svgBuilder = (path, perfix = 'icon') => {
  if (path === '') return
  idPerfix = perfix
  const res = findSvgFile(path)
  return {
    name: 'svg-transform',
    transformIndexHtml(html) {
      return html.replace(
          '<body>',
          `
          <body>
            <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" style="position: absolute; width: 0; height: 0">
              ${res.join('')}
            </svg>
        `
      )
    }
  }
}
